Apparatus for drawing fine threads of fibers of glass or the like



April 7, 1959 w. SCHULLER 2,880,457

APPARATUS FOR DRAWING FINE THREADS OF FIBERS OF GLASS OR THE LIKE FiledMay-12, 1955 APPARATUS FOR DRAWING FINE THREADS OF FIBERS OF GLASS ORTHE LIKE Werner Schuller, Alsager, England Application May 12, 1955,Serial No. 507,923

In Great Britain August 26, 1949 Public Law 619, August 23, 1954 Patentexpires August 26, 1969 2 Claims. (Cl. 18-8) The present inventionrelates to an apparatus for drawing fine threads, filaments or fibersfrom glass or other like material which is rendered fluid when heated.

Objects and advantages of the invention will be set forth in parthereinafter and in part-will ,be -obvious herefrom, or may be learned bypractice with the invention, the same being realized and attained bymeans of the parts, constructions, arrangements, combinations andimprovements pointed out in the appended claims.

The invention consists in the novel'partsfconstructions, arrangements,combinations and impt ovements herein shown and described. i

The accompanying drawing, referred to herein and constituting a parthereof, illustrates one embodiment of the invention, and together withthe description serves to explain the principles of the invention.

In one known process of drawing glass threads, one end of a glass rod isheated and the glass thread drawn by the drop of glass falling from thethread delivering position being connected to a winding mechanism. Inanother process, the thread leaving a container filled with liquid glassis brought into contact with a current of steam, air or other gasesflowing at high speed under pressure. In the latter process the speed ofmovement of the thread is greatest when the current of gas is conductedthrough a jet the construction of which is adapted to the expansion ofthe gas current under pressure so that all the compression forces aredirected towards increasing the speed of the thread. The effects on theglass thread would be particularly advantageous if the glass threadcould be introduced into this gas current in the jet. In the knownprocesses this has not been possible as there was no means to inject thethread into the jet. The practice hitherto has been to conduct thethread between two jets blowing on the thread from two sides of an acuteangle and thus effecting the forward movement of the thread. In thisway, due to the formation of whirling currents, a large part of thenecessary pressure is used up with a corresponding loss in speed.

A further disadvantage of known apparatus is that the glass drop has topass through the jets before the thread is formed. Owning to the largesize of the drops relatively to the thread, the space between the jets,which are positioned adjacent, has to be very wide; the required spacewould be much less if the thread alone were passed. The large distancebetween the jets causes an increased whirl formation within the threadarea and necessitates the use of an increased volume of steam and air.

These disadvantages are avoided by the apparatus according to theinvention, in which beneath the thread delivering position there isprovided, as a transport medium, a jet through which the thread passesand which surrounds the thread on all sides, the jet being connectedwith a drop conductor by a slit or narrow channel, both thecross-section of the jet and of the slit or channel being smaller thanthat of a thread-drop.

Figure 1 is a vertical section of apparatus according to the invention;

Figure 2 is a part horizontal section on the line II-II of Figure 1 on aslightly enlarged scale.

In the drawing, 1 denotes a thread-delivering position which may consistof the heated end of a glass rod or may be formed by the jet of acontainer for the molten glass.

According to the invention, a jet 2 surrounding the thread on all sides,is provided in a part 13 beneath the thread delivery position for thegaseous medium,

' such for example as steam. The cross-section of the jet 2 is less thanthe cross-section of a thread drop 3. The thread drop 3 normally drawswith it the thread 4. The jet 2 is connected with a drop conductor orconveyor 6 through a slit or narrow channel 5, which 5 is also of lessersection than the drop and which extends to the bottom of the part 13.The drop conductor 6is adapted to convey the glass drop 3 together withthe drawn thread 4 on to a receiving device, for example a winding drum7, which rotates in the direction of the arrow A and is positioned at asuitable distance below the part 13. At the bottom of the slit orchannel 5 there is provided a knife edge 8 over which the thread 4passes before being wound over the winding drum 7. The'jet 2 is providedwith a jet end 2a which extends into an annularchannel 9. The jet end211 is surrounded by the inner edge 10 of a conical part 11 of graduallyincreasing diameter. The outer end 12 of the part 11 is advantageouslyslightly bent to one side as illustrated in Figure 1, and screw-threadedinto a cavity formed to receive it in the lower part of the part 13.

The part 13 serves as base for the annular channel 9. In the part 13 isprovided a conduit 14 which is connected with the annular channels 9 bychannels 15, and through which the pressure medium passes to the annularchannels 9 around the jets 2.

In the example illustrated, the drop conductor or conveyor 6 is shapedin such manner that the drop is conducted first along a sloping part 16,from there to a position 17 whence the drop falls vertically on to thedrum 7, during which time the thread 4 while still connected to the dropis positioned at the lower part between the walls of the slit or channel5.

The apparatus operates as follows:

The glass drop 3 falls from the thread-delivering position 1, drawingwith it the thread 4, on to the thread conductor or conveyor 6, andslides downwardly over the sloping part 16 with the thread until itreaches the winding drum 7 on which the thread is wound. The pullexerted by the drum accelerates the downward movement of the thread,causing the thread to be drawn to a greater fineness. The pull of thewinding drum 7 also causes the thread to be severed from the drop at theknife edge 8, so that it is free to be subjected to the effects of thevacuum in the slit or channel 5 in which the lower part of the thread ispositioned and is then sucked into the jet opening 2a by the gaseous orother fluid medium flowing through the jet 2, and passes into theconical part 11 to be ejected through the part 12. The retarding of thethread 4 at the delivering position 1 imparts a waving movement to thethread and within the jet 2 which has for its eifect to increase thesuction of the gases to entrain the thread and draw it with them. Thiseffect is further increased by the elbow construction of the conicalpart 11 which forms continuous whirls of the fluid medium favourable forthe drawing or suction of the thread.

Owing to the thread being surrounded by the jet 2 the whole periphery ofthe thread is contacted by the drawing or suction medium and the threadis effectively drawn. Thus a continuous thread passes from the moltenglass reservoir through the jet, to be wound on a drum or in any othersuitable manner, and is interrupted only if the thread accidentallybreaks or when the apparatus is stopped. If a thread breaks by accident,a glass drop immediately reforms and a new thread is started; restartingis thus automatic.

The apparatus according to the invention makes it possible to reduce theconsumption of steam or air at the jet 2 to a minimum, which results incheaper production. The apparatus is also suitable for the manufactureof wool from the finest glass thread, or threads of other elasticmaterials.

As illustrated in Figure 2, a number of jets 2 can be provided injuxtaposition, the distance of the jets from each other being dependentonly on the diameters of the annular channels 9 which may beconsiderably smaller than those which to make the invention more clearhave been illustrated on an enlarged scale in the drawing.

The invention in its broader aspects is not limited to the specificcombinations and improvements described, but departures may be madetherefrom within the scope of the accompanying claims without departingfrom the principles of the invention and without sacrificing its chiefadvantages.

I claim:

1. In an apparatus for attenuating molten glass to filaments by theaction of a gaseous jet, the improvement comprising means disposed belowa source of molten glass to separate initial droplets of glass andincompletely attenuated filaments from completely at tenuated filamentssaid means comprising guide means including a sloped surface forreceiving said droplets, jet suction means disposed beneath said slopedsurface toward the high side thereof, severing means disposed below thelower edge of said sloped surface, a filament inlet means in the guidemeans including the sloped surface and extending from said severingmeans to said jet suction means, said filament inlet means being smallerthan said droplets, a rotating drum rotated below said severing means,the surface of said rotating drum being at least tangent to a plumb linefrom said severing means and means for rotating the drum in suchdirection as to increase the tension of the filament.

2. An improvement in an apparatus for attenuating molten glass tofilaments as set forth in claim 1, wherein the filament inlet comprisesa slit, the severing means consists of a severing edge, and the rotatingdrum increases the tension of the filament against the severing edge.

References (Iited in the file of this patent UNITED STATES PATENTS2,121,802, Kleist et al June 28, 1938 2,173,789 Nickles et al Sept. 19,1939 2,269,459 Kleist Ian. 13, 1942 2,526,775 Slayter et a1 Oct. 24,1950 2,535,561 Bastian Dec. 26, 1950 FOREIGN PATENTS 669,668 GreatBritain Apr. 9, 1952

